The present invention relates to securement systems for rollable mobility aids, and more particularly to such a system designed for securing a rollable mobility aid within a transit vehicle.
Various devices are known which allow physically disabled people to travel independently. Such devices, known generically as rollable mobility aids (or mobility aids), include wheelchairs, three-wheeled scooters, power bases, etc.
There are instances where an occupant of such a mobility aid must, for safety or other reasons, secure it to surrounding structure. Such an instance occurs when the occupant boards a transit vehicle such as a van, bus or train. Safety laws require that the transit vehicle be equipped with a device for securing the mobility aid within the vehicle.
The problem for designers of mobility aid securement systems is to design such securement devices with superior, fail-safe securement capability while at the same time being easy and quick to operate by both the mobility aid occupant and the bus driver. Several conventional systems have been proposed in the form of wheelchair restraint devices, but none have been completely satisfactory. For example, some conventional devices are strap/belt based which makes them difficult to use, as well as being time-consuming for bus drivers. Other proposals include mechanisms for clamping the wheels of a wheelchair in place but such mechanisms can damage the wheels and their corresponding rims if the bus swerves, is involved in an accident, or otherwise moves in such a way that causes the wheelchair to move with respect to the mechanism.
Still other conventional restraining devices include a post which extends downwardly from the wheelchair and is engaged by a vehicle-floor-mounted locking assembly such as is shown in U.S. Pat. Nos. 4,754,946 and 4,690,364, both to Constantin, and U.S. Pat. No. 4,973,022 to Mayland. Like the wheel clamp restraining devices, such floor-mounted restraining devices may be easily damaged in accident conditions because tilting of the wheelchair could cause the post to bend. Even worse, if the bus rides over a large bump, the wheelchair might be forced upward and become dislodged from the device. Such a result is obviously unacceptable.
Another conventional proposal is proposed in U.S. Pat. No. 4,265,478 to Korsgaard which discloses a thin latch plate mounted to tall, fixed, free-standing pillar stands that is latchable to a release bar mounted on a wheelchair. The restraining system in Korsgaard is unwieldy and its thin latch plate does not provide a latch mechanism that can withstand the rough treatment commonly encountered on transit vehicles. Such a latch mechanism will also be lacking in ability to resist tilting of the wheelchair.
It is a principal object of the present invention to provide a system which promotes securement of mobility aids to interior structure of transit vehicles, and which overcomes the drawbacks and limitations of prior art proposals. More specifically, the invention has as its objects the following:
(1) to provide such a system that achieves sustained securement in normal and accident conditions on the transit vehicle, and ensures that the mobility aid can be released from securement under all conditions;
(2) to provide such a system that is both easy to use by mobility aid occupants and transit vehicle operators having little skill, and requires a minimum of training;
(3) to provide such a system that promotes fast and easy securement even when mobility aid occupants approach it from various angles and positions;
(4) to provide such a system that is usable by occupants with limited use of their arms and hands;
(5) to provide such a system that is capable of absorbing shock from the transit vehicle and substantially lessening transfer of such shock to the mobility aid;
(6) to provide such a system that indicates when a securement condition exists, both locally to the aid occupant, and remotely to the transit driver;
(7) to develop a system with a release mechanism which can be actuated either locally by the occupant, or remotely by the driver;
(8) to develop an attachment concept that is usable with all commonly used mobility aids;
(9) to provide a mobility aid attachment system which can be retrofitted to existing transit vehicles and to existing mobility aids; and
(10) the provision of a securement system structure which can be locked in position while the vehicle is in motion.